 |
 |
Mechanism of dual CBS |
|
In the dual CBS, the hydraulic pressure generated on operation
of the right lever will act on the pistons on both ends of "three-pot"
calipers on the left and right of the front. The braking force
generated then will move the calipers on the left to generate
new hydraulic pressure on the secondary master cylinder.
The hydraulic pressure will act on the pistons on both ends
of three-pot calipers through the proportional control valve,
PCV, having the function of pressure reduction, to general braking
force on the rear wheel. Furthermore, the hydraulic pressure
generated by operation of the pedal will act on the piston in
the middle of three-pot calipers in the fore and aft. Similarly
to the lever brake, the braking force generated on the front
calipers on the left will generate hydraulic pressure in the
secondary master cylinder, which will act on the pistons on
both ends of the rear calipers. As the result, braking force
higher than the time of lever operation will be generated on
the rear wheel since all three pistons of the calipers are actuated.
Because of these mechanisms, the dual CBS turns out to be CBS
also when the lever is operated unlike the case of Combi Brake.
In addition to it, distribution characteristics different from
the time of operating pedal will be obtained.
|
|
Braking force distribution characteristics of dual CBS |
|
The above figure shows the braking force distribution characteristics
of dual CBS. The characteristics of pedal brake lies on the
ideal braking force distribution characteristic diagram at the
time of maximum loading, similarly to the case of Combi Brake.
The characteristics at the time of using the right lever brake,
on the other hand, exist on the underside along the ideal braking
force distribution characteristics in case of a single rider,
which indicates the braking force is distributed rather largely
on the front wheel. As the braking force on the front wheel
is increased, the braking force on the rear wheel increases
at first, then goes down after passing the peak. Such unique
distribution characteristics are obtained from the characteristics
of PCV exclusively of motorcycles with the function of pressure
reduction.
When both the pedal and lever are used, the distribution is
in the region lying between the two braking force distribution
characteristics, depending on the manner of distribution. This
will make it easy to obtain a distribution closer to the ideal
braking force distribution.
The above figure compares the deceleration generated by combination
of operation of the lever and pedal on completed vehicles between
the one equipped with conventional brake and that equipped with
dual CBS. The directional axis diagonally to the right (blue)
indicates lever input while the directional axis diagonally
to the left (red) shows pedal input and the direction along
the axis of ordinate (yellow) represents the deceleration generated
by combination of respective inputs.
The figure on the left shows the deceleration generated by the
combined operation of lever and pedal in the conventional brake
system. It can be seen that both of the values of input and
generated deceleration are low in the single operation by pedal
input while high deceleration generated by the combination with
lever input takes place in a partly limited input distribution
area surrounded by green.
The figure on the right shows the deceleration generated by
dual CBS. It can be seen that the operation of pedal alone enables
to yield high input and high deceleration and that the area
in which high deceleration can be generated is expanded. This
means that riders can generate high deceleration much more easily.
|
|
 |
|
|
